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本文提出了一种快速测定糙米中有机磷农药的简单方法。本方法采用乙腈—水(1+1)萃取,醋酸锌去除植物油,然后在活性炭层析柱上淋洗。萃取液中的高脂肪酸迅速与醋酸锌反应,生成不溶性的羧酸锌沉淀。添加的物质引起的干扰通过活性炭层析柱去除,被活性炭吸附的有机磷农药用丙酮—正己烷(1+1)淋洗下来。由于乐果不被活性炭吸附,所以应该用二氯甲烷将其从乙腈—水洗脱液中萃取出来。农药的含量用气象色谱火焰光度法测定。往50克糙米样品中加入:5—50微克二嗪农、6—30微克对硫磷、8—40微克杀螟松和IBP、10—50微克乐果和倍硫磷、20—100微克马拉硫磷或40—200微克EPN,它们的回收率在77.7％至95.8％范围内。
This paper presents a simple method for rapid determination of organophosphorus pesticides in brown rice. The method uses acetonitrile - water (1 + 1) extraction, zinc acetate to remove vegetable oil, and then rinsed on an activated carbon column. High fatty acids in the extract rapidly react with zinc acetate to form insoluble zinc carboxylates. The interference caused by the added substance is removed by an activated carbon column, and the organophosphorus pesticide adsorbed on activated carbon is eluted with acetone-n-hexane (1 + 1). Since dimethoate is not adsorbed on activated carbon, it should be extracted with methylene chloride from the acetonitrile-water eluent. The content of pesticides was determined by gas chromatography flame photometry. To 50 grams of brown rice samples were added: 5-50 micrograms diazinon, 6-30 micrograms parathion, 8-40 micrograms fenitrothion and IBP, 10-50 micrograms dimethoate, and 20-100 micrograms horse The results showed that the recoveries ranged from 77.7% to 95.8%.